1. Field of the Invention
The present invention relates to devices, methods and apparatus to treat obesity. Implantable devices, methods to implant implantable devices, and surgical devices to enable the implantation of the implantable devices in, around, or near the walls of organs or vessels are disclosed, including devices to appose the walls of the stomach. Feedback systems are also disclosed which enable multimodality therapy such as gastric restriction in combination with electrical stimulation of the stomach, sensing of feeding parameters, and/or other efferent or afferent neural pathways in a patient.
2. Description of the Related Art
Obesity is a public health problem of extreme national and international importance. There are an estimated 60 million obese adults and 2 million obese adolescents in the United States as of 2004. By some estimates, there are 1 billion obese individuals worldwide. Indeed, to highlight the worldwide importance of the disease, a recent report estimated that over there are over 60 million obese individuals in China, a 10-fold increase since 2000. Obesity affects the life quality and productivity of those effected and leads to long-term health related complications such as diabetes and heart disease. Some researchers estimate that if the obesity epidemic is not brought under control, it could quickly overwhelm societal resources.
To date, surgery is the only proven method for inducing substantial weight loss. The mechanism behind the success of surgery is, in many cases, not known because obesity is such a complex, multifactorial disease. Some researchers propose that surgery does no more than provide biofeedback for appetite retraining. Other researchers maintain that surgery alters the physiology of the patient such that satiety is induced earlier or fewer nutrients are absorbed. Nonetheless, the consensus among most obesity researchers is that at the current time, long-term weight loss is only possible by surgical means and that the success of surgery is due to a multifactorial set of changes.
Over the past four decades, there have been numerous surgical procedures and devices developed to treat those who suffer from morbid obesity. In general, there are two physiologic components of all past and current procedures: malabsorption and mechanical restriction/volume reduction. Newer methods and devices include stimulation devices such as neurostimulators and muscle stimulators. In general, these devices will require further research and development before they will be used to treat obese patients as a single therapy.
Many of the procedures performed in the past have proven to be impractical, dangerous, and/or detrimental to patient health and are now of historical importance only. One example of a failed procedure was the jejuno-ileo bypass in which a malabsorptive state was created through the bypass of a large portion of the intestine through the creation of a surgical anastomosis between the jejunum and the ileum. While patients initially lost a great deal of weight, liver failure or liver damage occurred in over one-third of the patients, necessitating reversal of the surgical procedures.
One of the first restrictive type surgical procedures was the so-called “stomach stapling” operation in which a row of horizontal staples was placed across the upper stomach and then several staples were removed from the staple line to create an opening, the “os,” for a small amount of food, but not too much food. This procedure was mostly restrictive, leading to an early feeling of satiety. This surgery was abandoned because 70%-80% of patients had inadequate weight loss due to staple line dehiscence (i.e. the staples pulled through the stomach wall). A procedure to stabilize the staple line was performed by Smith et. al. (Lindsay B. Smith; Modification of the Gastric Partitioning Operation For Morbid Obesity. Am. J. Surgery 142, December 1981) in which the staple line was buttressed in the region where the staples were removed using teflon pledgets with sutures passing through the middle of the pledgets. The purpose of the pledgets was to buttress the suture and distribute the load across the suture to the pledget, thereby preventing the suture from pulling through the stomach and therefore stabilizing the os. The outcomes showed that the suture buttress was unequivocally able to prevent the suture from tearing through the stomach wall; indeed, over 90% of the patients showed excellent weight loss at 18 months.
The Roux-en-Y (The Roux) bypass operation has become the most commonly performed surgical procedure to treat the morbidly obese in the United States. It combines a small degree of malabsorption with a 90% reduction in the volume of the stomach. In the United States, 150,000 Roux procedures were performed in the year 2004. This number is expected to rise to 500,000 procedures by 2007. The procedure actually has been performed since the late 1970's but has evolved substantially over the past three decades into a relatively safe and effective procedure; indeed, the long-term data are very good. The advent of laparoscopic surgery and hence the laparoscopic Roux-en-Y bypass in combination with excellent follow-up results from the open (and laparoscopic) procedure are reasons for the proliferation of the Roux procedure.
Despite the efficacy of the Roux procedure and the recent laparoscopic improvements, it remains a highly invasive procedure with substantial morbidity, including a 1-2% surgical mortality, a 20-30% incidence of pulmonary morbidity such as pneumonia, pulmonary embolism, etc., and a 1-4% chance of leak at the anastomotic site which can result in a spectrum of consequences ranging from an extended hospital stay to death. Furthermore, it is not a good option for adolescents in whom the long-term consequences of malabsorption are not known. In addition, many patients resist such an irreversible, life altering procedure.
The Roux procedure requires general anesthesia and muscle paralysis which, in the morbidly obese population, is not of small consequence. There is also a substantial rate of anastomotic stricture which results in severe lifestyle changes for patients. As an example, many patients are forced to vomit after meals. Furthermore, although minor when compared to previous malabsorptive (e.g. jejuno-ileal bypass) procedures, the malabsorption created by the Roux-en-Y procedure can dramatically affect the quality of life of patients who undergo the procedure; for example, they may experience gas bloating, symptoms of the dumping syndrome, and/or dysphasia. In addition, these patients can experience very early fullness such that they are forced to vomit following meals.
Recently, minimally invasive procedures and devices which create a feeling of early satiety have been introduced into the marketplace in an attempt to address some of the issues above. The LAP-BAND™ is a band which encircles the stomach at the region of the fundus-cardia junction; it is a restrictive procedure similar to stomach stapling. It requires general anesthesia, a pneumoperitoneum, muscle paralysis, and extensive dissection of the stomach at the level the gastroesophageal junction. It also requires continual adjustment of the band, or restriction portion of the device. Although less invasive than the Roux procedure and potentially reversible, the LAP-BAND™ is nonetheless quite invasive. It also does not reduce the volume of the stomach by any great extent and some patients report a feeling of hunger much of the time. Furthermore, once implanted, the Lap-Band™, although it is adjustable by percutaneous means, is in fact very difficult to adjust and many iterative adjustments are required before it is made right.
Long-term clinical follow-up reveals that the banding procedure results in many complications. In a recently published article (Camerini et. al. Thirteen Years of Follow-up in Patients with Adjustable Silicone Gastric Banding for Obesity: Weight Loss and Constant Rate of Late Specific Complications. Obesity Surgery, 14, 1343-1348), the authors reported a 60% prevalence of late band removal secondary to complications such as erosion, slippage of the band, infection, or lack of effectiveness. Nonetheless, the LAP-BAND™ as a procedure is becoming very popular across the world as it is a less invasive and reversible procedure. The weight loss in long-term trials is considered adequate by some and inadequate by many; across various studies, the average weight loss is approximately 40% of excess body weight which is well below the weight loss in the Roux, VBG, and duodenal switch procedures (see below).
Other procedures which have been tried in the past and which offer varying degrees of weight loss include several variations of the original “gastroplasty” procedures. These procedures represent an evolution of the so-called “stomach stapling” procedure discussed above. These procedures were attempted prior to and concomitant with the evolution of the Roux-en-Y. They became popular (despite offering less weight loss than the Roux) because of their substantially less invasive nature and possible reversibility.
One such example is called the vertical banded gastroplasty, or VBG, which again, involves the creation of a restricting “os” for food. In the VBG, the border of the “os” is the lesser curvature of the stomach which is less apt to dilate than the fundus region of the stomach. Furthermore, the procedure completely excludes the fundus which is thought to easily dilate and in fact, is physiologically “programmed” to dilate during meals . . . so-called “receptive relaxation.” Dilation of the fundus as a result of continued overeating is a major reason for failure of the Lap-Band and in some cases the Roux procedure and the development of the VBG was intended to improve upon these outcomes. One issue with the VBG is that, as practiced today, it is not reversible, nor is it adjustable, and it is difficult to perform laparoscopically. As in the horizontal gastroplasty, the VBG utilizes standard staplers which, as in the horizontal gastroplasty, are unreliable when applied to the stomach. In the case of the VBG, the row of staples runs parallel to the lesser curvature of the stomach. An important reason for recurrent weight gain in the VBG is in fact recannulation of the staple line, leading to a so-called gastro-gastric fistula.
A recent, prospective, randomized trial, compared the VBG to the adjustable banding procedure and found that the VBG was overwhelmingly superior to the banding procedure (Morino et. al. Laparoscopic Adjustable Silicone Gastric Banding Versus Vertical Banded Gastroplasty in Morbidly Obese Patients. Annals of Surgery. Vol. 238 (6) pps. 835-842). Twenty five percent of the patients in the banding group returned to the operating room whereas there were no returns to the operating room in the gastroplasty group. The degree of weight loss was close to 60% of excess body weight after three years in the gastroplasty group and closer to 40% of excess body weight in the banding group. Although in this study, the VBG was successfully performed laparoscopically, the laparoscopic VBG procedure is in fact, difficult to perform, because the procedure is not standardized and a “tool box” does not exist for the surgeon to carry out the procedure; furthermore, the procedure is not a reversible one and relies on the inherently unreliable stapler systems.
A recent meta-analysis and systematic review (Buchwald et. al. Bariatric Surgery: A Systematic Review and Meta-analysis; JAMA vol. 292, no 14. pps 1724-1737) indicated that vertical gastroplasty (avg. excess weight loss of 68.2%) is superior to adjustable banding (avg excess weight loss of 47.5%) and gastric bypass (avg excess weight loss of 61.6%).
The Magenstrasse and Mill (M&M) procedure is an evolving gastroplasty technique wherein the greater curvature of the stomach is separated (stapled and cut) from the path of food, leaving a tube of stomach, the Magenstrasse, or “street of the stomach,” which is comprised of the lesser curvature. This procedure is similar to the VBG except that the longitudinal staple line of the stomach extends further along the lesser curvature and into the antrum. The theory behind leaving the antral “mill” is that it will continue to serve its normal function of mixing, grinding, retropulsion, and well-orchestrated expulsion of chyme into the duodenum. An authoritative study on the operation is incorporated herein by reference (Johnston et. al. The Magenstrasse and Mill Operation for Morbid Obesity; Obesity Surgery 13, 10-16).
In summary, the vertical gastroplasty procedure appears to be superior to the banding procedure. However, the vertical gastroplasty procedure is not easily performed laparoscopically and furthermore, it is not easily reversible. Therefore, a need exists to standardize the vertical banded gastroplasty and create a safer procedure which is also easy to perform, is durable, and is reversible.
The intragastric balloon is not a new concept. The intragastric balloon is meant to displace volume within the stomach such that a smaller volume of food leads to an earlier feeling of satiety. Currently, intragastric balloons on the market are not fixed to the stomach and consequently, can lead to complications such as obstruction and mucosal erosion. To avoid these complications, the balloons are removed after a maximum of six months. In a prospective, non-randomized, unblinded study (Sallet et. al. Brazilian Multicenter Study of the Intragastric Balloon; Obesity Surgery, 14, 991-998), the average excess weight loss was 48.3% after 1 year. However, the incidence of nausea and vomiting was 40% and epigastric pain was 20%; balloon impaction occurred in 0.6% of patients. A balloon which is fixed to the wall of the stomach could potentially improve the intragastric balloon device and allow longer-term implantation.
More recently, there has been an effort to develop even less invasive devices and procedures which do not involve incisions at all. For the most part, these procedures are performed from within the stomach with an endoscope and by a physician with a high degree of endoscopic skill. For example, U.S. Pat. No. 6,558,400 describes methods and devices to create partitions in the stomach. Anchors or staplers applied through an endoscope from within the stomach are used to accomplish the partitions. Similarly, U.S. Patent Application Publication No. 2004/0122456 describes another set of methods and devices to reduce the volume of the stomach. Expandable anchors are deployed both on the anterior and posterior wall of the stomach using an endoscope. Flexible sutures are brought out of the patient's mouth and the sutures are crimped together within the stomach in order to bring the walls of the stomach closer together. The final configuration has a discontinuous connector positioned between the anterior and posterior anchors. U.S. Pat. No. 6,773,440 describes a device which is advanced through an endoscope and grasps or applies suction to a fold of mucosa to apply anchors through the mucosal and serosal layers of the stomach.
Endoscopic procedures to manipulate the stomach can be time consuming because of the technical difficulty of the endoscopy; they also require a large endoscope through which many instruments need to be placed for these complex procedures. Due to the large size of the endoscope, patients typically will require general anesthesia, which limits the “non-invasive” aspects of the procedure. Furthermore, the procedures require advanced endoscopic skill which would need to be acquired by most endoscopic practitioners outside of academic institutions. Such skill adaptation can take a significant amount of time, which will limit adoption of the procedure by the physician community. A further issue is that there is a limitation on the size of the anchors and devices which can be placed in the stomach because the endoscope has a maximum permissible size.
Percutaneous Endoscopic Gastrostomy (PEG) refers to a procedure in which a gastrocutaneous tract is created using a percutaneous procedure (see below for definition). A recent update of the procedure can be found on the Society of American Gastrointestinal Endoscopic Surgeons (SAGES) website, and is incorporated herein by reference. Briefly, the procedure involves insufflation of the stomach with and under visualization with an endoscope. A small incision is made in the skin and a needle is advanced into the stomach (the stomach sits just under the abdominal wall when insufflated) under endoscopic visualization. A feeding tube is then placed over the needle to create a gastrocutaneous tract with the feeding tube inside the tract with the needle subsequently removed. The feeding tube is secured with an external bolster to creates a tubular tract from outside the patient through the skin of the abdominal wall and residing inside the stomach. Over the ensuing weeks, a permanent tract evolves between the stomach mucosa and epithelium of the skin, after which, the bolster can be removed without consequence. When the feeding tube is to be removed, the gastrocutaneous tract will close on its own as food will preferentially be delivered antegrade (the path of least resistance) to the duodenum, thereby allowing the tract to heal.